Current surge indicators using a magnetic drive are known as in Soviet Patent 1,215,068 (86.02.28).
In suspended power transmission lines which are suspended by insulators connected to grounded towers, ground faults as a result of insulator flashover or failure are common. When these ground faults occur, the transmission line overload protection circuits may detect the surge of current and shut down the entire line. Since the insulator flashover may occur without damaging the insulator and leaving a noticeable indication of where the flashover occurred, the power line may be put back into use without maintenance personnel being able to detect where on the transmission line the failure occurred. In the case of insulator failure, it is difficult to locate the faulty insulator for replacement purposes. Detailed visual inspection of all insulators may be required. In the case of lightning striking a tower, it is useful to know where the lightning struk to check whether any permanent damage to the tower, insulator or transmission line has occurred.
Therefore, it is important to provide a way to indicate on which power transmission line or on which insulator anchor line a current surge has occurred in order to indicate where the ground fault took place.